The present invention is directed generally to centrifugal liquid processing systems and apparatus, and more particularly to a lubrication system for such apparatus.
Centrifugal liquid processing systems, wherein a liquid having a suspended mass therein is subjected to centrifugal forces to obtain separation of the suspended mass, have found application in a wide variety of fields. For example, in recent years the long term storage of human blood has been accomplished by separating out the plasma component of the blood and freezing the remaining red blood cell component in a liquid medium such as glycerol. Prior to use the glycerolized red blood cells are thawed and pumped into the centrifugating wash chamber of a centrifugal liquid processing apparatus where, while being held in place by centrifugation, they are washed with a saline solution which displaces the glycerol preservative. The resulting reconstituted blood is then removed from the wash chamber and packaged for use.
The aforedescribed blood conditioning process, like other processes wherein a liquid is caused to flow through a suspended mass under centrifugation, necessitates the transfer of solutions into and out of the rotating wash chamber while the chamber is in motion. In the case of the aforedescribed blood processing operation, glycerolized red blood cells and saline solution are passed into the wash chamber, and waste and reconstituted blood solutions are passed from the chamber. To avoid contamination of these solutions, or exposure of persons involved in the processing operation to the solutions, the transfer operations are preferably carried out within a sealed flow system, preferably formed of a flexible plastic or similar material which can be disposed of after each use.
One centrifugal processing system particularly well adapted for such use is that described and claimed in the co-pending applications of Houshang Lolachi, Ser. Nos. 562,748 and 562,749, filed on Mar. 27, 1975 and assigned to the present assignee. This system established fluid communication between the rotating chamber and the stationary reservoirs through a flexible interconnecting umbilical cord without the use of rotating seals, which are expensive to manufacture and add the possibility of contamination of the blood being processed. In one preferred embodiment of this system a rotatably driven sleeve is provided on the end of a rotatably driven arm to guide the umbilical tube as the wash chamber rotates. This sleeve has proven difficult to lubricate in practice, the relatively high centrifugal forces present on the sleeve precluding the reliable long term operation of self-lubricated bearings, and the difficulty of establishing fluid communication with the rotating element precluding the use of pressure lubrication systems for this purpose. The present invention is directed to a lubrication system for such centrifugal liquid processing apparatus which is entirely automatic in operation and which may be added without substantial modification to the apparatus.